The Rickettsiae 387 



HUMAN RICKETTSIALPOX 



This recently recognized disease caused by Rickettsia akari is 

 transmitted bv the mite Allodermamjssus sanguineus, and the chni- 

 cal s\'mptoms resemble those of chickenpox. The first case was 

 discovered in New York City in 1946, and since then Connecticut 

 and Massachusetts have also reported finding cases of this disease. 

 Undoubtedly other parts of the United States will report additional 

 cases when they are recognized. 



The mite bites house mice (Mtis musculis) and man, and the 

 causative rickettsiae have been isolated from mites, mice, and in- 

 fected human beings. When cultivated in embryonated eggs, the 

 rickettsiae are found localized both intra-nuclearly and intra- 

 cytoplasmically in the yolk sac cells. 



Mites gather on the warm walls where heating ducts pass to 

 the upper floors, and the cases reported to date have localized in 

 apartment houses where rodents are a problem. Although the 

 disease is accompanied by an inflammation of the lungs, the mor- 

 tality rate is low. 



"Q" FEVER 



In 1936 Derrick of Queensland, Australia, was studying a febrile 

 disease which had clinical symptoms resembling those of influenza. 

 He injected some blood and some urine of a patient into a guinea 

 pig and the pig became ill. After recovering from the disease, the 

 pig displayed an immunity to subsequent injections of like mate- 

 rial. The causative organisms were finally isolated from a mouse 

 which had been injected with blood from an infected patient. 

 Textbooks frequently give the impression that "Q" fever derives 

 its name from Queensland where it was studied, but Derrick claims 

 that it was the questionable nature of the disease that led him to 

 call it "Q" fever. 



This disease may be more common than is generally believed, 

 and many cases of questionable influenza might well be "Q" fever 

 if subjected to thorough diagnostic studies. Persons engaged in 

 occupations which bring them in close contact with animals are 

 most likelv to contract the disease. Those who handle hides, work 



